МНОГОФАЗНО-ОДНОФАЗНыЕ РЕВЕРСИВНыЕ ЭЛЕКТРОМАШИННО-ВЕНТИЛЬНыЕ ПРЕОБРАЗОВАТЕЛИ БЕСКОНТАКТНыХ МАШИН ДВОЙНОГО ПИТАНИЯ

Розглянуто процеси в багатофазно-однофазних реверсивних електромашинно-вентильних перетворю- вачах безконтактних машин подвійного живлення. Рассмотрены процессы в многофазно-однофазных реверсивных электромашинно-вентильных преобра- зователях бесконтактных машин двойного питания

Alkalicyamelurates, M3[C6N7O3].xH2O, M = Li, Na, K, Rb, Cs: UV-luminescent and thermally very stable ionic tri-s-triazine derivatives.

Cyamelurates are salts of cyameluric acid, a derivative of tri-s-triazine (1,3,4,6,7,9-hexaazacyclo[3.3.3]azine or s-heptazine). These compounds are thermally very stable and possess interesting structural and optical properties. Only very few tri-s-triazine derivatives have been reported in the literature. The water-soluble alkali cyamelurates were extensively characterized using NMR, FTIR, Raman, UV, luminescence spectroscopy and elemental analysis. In addition, the single crystal X-ray structure analyses of the four hydrates of lithium, sodium, potassium and rubidium cyamelurates (Li(3)[C(6)N(7)O(3)].6H(2)O; Na(3)[C(6)N(7)O(3)].4.5H(2)O; K(3)[C(6)N(7)O(3)].3H(2)O; Rb(3)[C(6)N(7)O(3)].3H(2)O) are presented. Thermogravimetric analysis shows that the dehydrated salts start to decompose at temperatures above 500 degrees C. The thermal stability does not depend on the cations which is in contrast to the analogous s-triazine salts, i.e. the alkali cyanurates M(3)[C(3)N(3)O(3)]. The photoluminescence spectra indicate a very strong solid state UV-emission with maxima between 280 and 400 nm

New ceramic phases in the ternary Si-C-N system

The solid state chemistry of nitrides was relatively neglected in the past, compared with the research of the solid state chemistry of oxide compounds, although there has been considerable activity in this area over the past two decades. In contrast to numerous studies on carbon nitride phases initiated by the postulation of a "superhard" C 3N 4 phase, investigations of ternary Si -C-N compounds remain sparse. The compounds Si(NCN) 2 and Si 2C 2(NCN) were the first ternary crystalline phases in the SiCN system synthesized at ambient pressure. The present review highlights recent developments in the synthesis of binary C-N and ternary Si-C-N materials under high pressure and high temperature reaction conditions. The new materials are predicted to exhibit unique properties, such as a high level of hardness, or interesting magnetic and optoelectronic features

Single-crystals of a new carbon nitride phase with all-sp³ carbon

We prepared a carbon nitride compound by treating the molecular precursor C2N4H4in a laser-heated diamond-anvil-cell (LH-DAC) at pressures exceeding 27 GPa and temperatures above 1700°C. After quenching we recovered single crystals of the new material with diameters of about 1 μm. Using several experimental characterization techniques in conjunction with computational methods we determined composition, hybridization of constituting atoms, and the crystal structure. The new carbon nitride imide, C2N2(NH), adopts a defect-wurtzite structure and is isotypic to Si2N2(NH). © 2007 Materials Research Society

High-pressure high-temperature synthesis of novel binary and ternary nitride phases of group 4 and 14 elements

Our recent experiments on high-pressure high-temperature synthesis of novel ternary nitrides of group 4 and 14 elements are presented. Dense carbon nitride imide, C₂N₂(NH), was synthesized for the first time in a laser heated diamond anvil cell (LH-DAC) at pressures above 27 GPa and temperatures around 2000 K. Based on results of the electron diffraction-, EELS-and SIMS-measurements combined with theoretical calculations the structure of this new C-N-H phase was suggested to be of the defect-wurtzite type. Farther, macroscopic amounts of a new oxynitride of zirconium having cubic Th₃P₄-type structure, c-Zr₂.₈₆(N0.₈₈O₀.₁₂)₄, were synthesized at high pressures and temperatures using a multi-anvil apparatus. Earlier this structure was observed for binary nitrides of zirconium(IV) and hafnium(IV) synthesized in microscopic amounts in a LH-DAC. The lattice parameter of c-Zr₂.₈₆(N0.₈₈O₀.₁₂)₄ was found to be a₀ = 6.7549(1) Å which is slightly larger than that of c-Zr₃N₄. Isotropic bulk and shear moduli of c-Zr₂.₈₆(N0.₈₈O₀.₁₂)₄ of B₀ = 219 GPa and G₀ = 96 GPa, respectively, were determined from the compression and nanoindentation measurements. The Vickers microhardness, HV(1), of the porous (about 30 vol. %) sample of c-Zr₂.₈₆(N0.₈₈O₀.₁₂)₄ was measured to be 12 GPa, similar to that of single crystal δ-ZrN

High-pressure high-temperature synthesis of novel binary and ternary nitride phases of group 4 and 14 elements

Our recent experiments on high-pressure high-temperature synthesis of novel ternary nitrides of group 4 and 14 elements are presented. Dense carbon nitride imide, C2N2(NH), was synthesized for the first time in a laser heated diamond anvil cell (LH-DAC) at pressures above 27 GPa and temperatures around 2000 K. Based on results of the electron diffraction-, EELS-and SIMS-measurements combined with theoretical calculations the structure of this new C-N-H phase was suggested to be of the defect-wurtzite type. Farther, macroscopic amounts of a new oxynitride of zirconium having cubic Th3P4-type structure, c-Zr2.86(N0.88O0.12)4, were synthesized at high pressures and temperatures using a multi-anvil apparatus. Earlier this structure was observed for binary nitrides of zirconium(IV) and hafnium(IV) synthesized in microscopic amounts in a LH-DAC. The lattice parameter of c-Zr2.86(N0.88O0.12)4 was found to be a0 = 6.7549(1) Å which is slightly larger than that of c-Zr3N4. Isotropic bulk and shear moduli of c-Zr2.86(N0.88O0.12)4 of B0 = 219 GPa and G0 = 96 GPa, respectively, were determined from the compression and nanoindentation measurements. The Vickers microhardness, HV(1), of the porous (about 30 vol. %) sample of c-Zr2.86(N0.88O0.12)4 was measured to be 12 GPa, similar to that of single crystal δ-ZrN